High above London, on the rooftops of the city, lives a secret society of misfits governed by a bizarre code of honour. It is a world known to only a few people on the streets below - until the murderous battle for its leadership breaks out.

As the Roofworld fights to keep the powerfully evil Chymes and his occult worshipping followers at bay, Robert Linden and Rose Leonard, two innocent outsiders, are drawn into a twilight, dangerous world.

They face far greater terrors than they could have imagined. And the battle is on for the ultimate prize - London itself.